RPM going crazy when engine is hot

[chajieun90]

Hello. I have 1994 MAZDA MX-3 with rpm going crazy even I didn't step on accelerator.
please check youtube video link below
https://www.youtube.com/watch?v=1CoZl95odx4

I already changed lots of parts to fix this problem but every time failed. I'm going crazy with this!
distributor cap, oxygen sensor, throttle position sensor, spark plug, valve cover gasket, coolant temperature sensor, oil changed.
and also cleaned throttle body and egr valve.

it was pretty nice right after cleaned egr valve yesterday. and today it cames again with engine check light turns on once and go out.
i also checked diagnostic but nothing comes out.

any idea can be helpful.. please help!

[speedray]

Hello,

First question, have you tried retrieving the diag codes?

Second, the RPM's is from the crankshaft sensor by the flywheel, have you checked or replaced this and also check the the wiring is ok going to it.

[mitmaks]

Have you adjusted throttle position sensor? You can't just install one and be done with it. It has to be adjusted according to repair manual.

[Demonic1]

mitmaks is on the right path.
Here's the write-up on the throttle body cleaning and adjusting
viewtopic.php?f=3&t=42551
and the second page
viewtopic.php?f=3&t=42552